Gesellschaft ftjr zink-industrie



(No Modem M. SCHROEDER. PROCESS OF PRODUCING GLUE AND GBLATINE FROMBONES. No. 518,861.

Patented Ap' r. 24, 1894,

INVENTOR WITNESSES: I

MAX SOHROEDER, oFpUssELDoRF, 'Ass enon or ONE-HALF TO THE AOTIEN-GESELLSOHAFT FUR ZINK-INDUSTRIE, VORMALS WILHELM GRILLO, OF

OBERHAUSEN, GERMANY.

PROCESS OF PRODUCING GLUE AN'D GELATllNE FROM BONES.

SPECIF IQATIOJM' forming part of LettersPatent No. 518,861 dated .April24-, 1894.

Application filed March 10.1894. Serial No. 503.127. (N specimens.)

T0 at whom it may concern;

Be it known that I, MAX SOHROEDER, asubject of the German Emperor,residing in Dusseldorf, Germany, haveinvented certain new and usefulImprovements in Processes of Producing Glue and Gelatine from Bones, ofwhich the following is a specification.

This invention relates to an improved process for the production of glueand gelatine from bones. Hitherto the manufacture of glue from ordinarybone material has been once bring about a strong decomposition of theglue-substance, there is obtained only a dark brown glue of smallcommercial value. Much better is the glue produced by the second processbecause the extracted cartilage may be easily boiled down to aglue-solution at temperatures of 100 Celsius and under, but

this process is somewhat costly in consequence of the great expense forthe acid and the requisite preparation of the solutions.

The object of this invention is to obtain.

3 5 good serviceable glue and gelatine from bones by producing first thedry disintegration of the same without dissolving the phosphates bymeans of gaseous sulphurous acid; then decomposing the brittle bones bymeans of 40 steam or boiling water into an acid glue-solution containingsome acid calcium-sulfite andbi-calcium phosphate, and a residuumconsisting substantially of mono-calcium phosphate, a neutral sulfite ofcalcium and some undissolved organic substances. 2

My invention is based on the fact thatbones containing some moisturehavea peculiar capacity for absorbing gaseous sulphurous acid. It, atthe ordinary temperature, a current of sulphurous acid gas be passedthroughairdried or slightly-moistened bones placed in a closedreceiver,it will be found that the quantity of sulphurous acid passing out at thetop of the receiver does not correspond to that introduced at thebottom-part of the vessel.At the commencement, the sulphurous acid gasis almost wholly absorbed by the bones; later on, the absorptionproceeds more slowlyso that a portion of the sulphurous acid escapes atthe top of the receiver. In the course of twelve hours, the bones, withthe exception of those of the very hard tubular kind, will have absorbedsulphurous acid to the extent of from ten to twelve per cent. of theirweight. If the current of sulphurous acid be continued, still more andmore of the same will be taken up by the bones'and it may withoutdifficulty rise to fifteen and even twenty per cent. of the weight ofthe bones. It the bones be then removed from the closed receiver andexposed for a length of time to the air, they will be found to give offsulphurous acid gas but only until the sulphurous acid contained in thebones is reduced to about eleven to twelve per cent. These contents ofsulphurous acid remain constant even when the bones are exposed to theair for months, neither is the sulphurous acid contained in the sameexpelled by heat, or water, or by a current of steam. From theseobservations it may be deduced that by the absorption of from eleven totwelve percent. of sulphurous acid the point of saturation of the boneshas been reached, while the quantity of gas which is absorbed above thispercentage is held temporarily only either by the capacity forcondensation possessed by porous bodies or bya slight chemical bindingaction.

As the chemical binding of the sulphurous acid is not due to thecartilage-substance of 0' the bones, the absorption of sulphurous acidis due to and attained only by the thorough conversion of the phosphatesin the bones.

It is known that, on an average, bones consist of one third of organicand two thirds of 5 inorganic substances, the latter irrespective of thesmall quantity of carbonate, consisting mainly of phosphate of lime. Itnow the absorption of from eleven to twelve per cent. of sulphurous acidbe attributed to the inor- 10 ganic portion only of the bones, thereresults an absorption by the same of from sixteen to seventeen per cent.of sulphurous acid. The conversion of the bone-phosphates wouldtherefore proceed substantially in accordance with the followingequation, which presupposes an absorption of 16.3 per cent. ofsulphurous acid:

With this assumption corresponds the fact that the phosphate has passedover into a water-soluble form. Whether during this conversion anabsorption of water of crystallization takes place, is of littleimportance for the successful carrying out of the process. The ordinaryamount of moisture which the bones contain, is as a rule suflicient forthe requirements of the conversion, and if this should not be the case,it might easily be increased by a previous addition of some moisturethereto. Bones thoroughly dried at a temperature of Celsius possess onlya small capacity for taking up sulphurous acid because they aredeficient in the water necessary for the aforesaid conversion.

Instead of the pure gaseous sulph urous acid, mixtures of the same withnitrogen, oxygen, carbonic acid and other indifierent gases may beemployed, but with a high degree of dilution the conversion of thephosphates of the bones is retarded. On the other hand, by employing ahigher pressure and a corresponding compression of the activegas-molecules, the conversion may be considerably accelerated.

My improved process would have but little value if it were notaccompanied by a marked change in thestructure of the bones. By theconversion of the phosphates, the thinner and somewhat elastic bones arerendered quite brittle and may be broken into small pieces without muchdifficulty. In consequence of their loose or spongy structure, theyoffer but slight resistance to boiling water, and are boiled at 100Celsius and less into glue nearly as quickly as the pure extractedcartilage. The sulphite and phosphate in the brittle bones are changedinto powder-form after only two hours boiling; stronger and tougherbones are rendered so soft that they may be indented with the fingers;and only the inner portions of hard tubular bones which are notsufficiently acted upon by the sulphurous acid retain their structure.The gluesolution thus obtained is of a bright color but somewhat milkyowing to the phosphate distributed therein. It also contains salts insolution and reacts strongly acid. It is therefore not suitable forimmediate working up into glue. The salts resulting from the conversion-process, namely the neutral calciumsulfite and mono-calciumphosphate, are insoluble in water, but as in practice a small excess ofsulphurous acid is unavoidable by reason of the condensing action of thebones, there will be found in the solution small quantities of acidcalcium-sulfite and bi-calciumphosphate. These salts are not retained insolution during the concentrating and drying of the glue, but render thesame opaque. This objectionable feature may be removed by neutralizingthe glue-solution with milk of lime. By this means not only is theacid-reaction suppressed, but nearly all the salts except, a smalluninjurious residue, are precipitated in an easily filtered form andcarry with them all other impurities so that the result is a perfectlyclear neutral glue-solution, mostly of a bright yellow color, whichsolution may be worked up into glue in the known way.

The accompanying drawing represents a side-elevation, partly in section,of one form of apparatus which can be used for carrying into practice myimproved process for treating bones with gaseous sulphurous acid, thedrawing representing a battery of eight receivers for the broken bones,in which the bones are successively treated with sulphurous acid gas.

The bones to be treated may have their fat previously removed or not,the previous extraction of the fat, however having the advantage thatthe badly-smelling substances are removed at the same time and the poresof the bones opened for the reception of the sulphurous acid vapors. Thebones are pref- 'erably reduced to small pieces by mechanical means,whereby the absorption of the sulphurous acid and the conversion of thebones is accelerated.

The apparatus shown in the drawing consists of a battery of preferablyeight air-tight receivers A, A A &c., which are made of wood lined withlead, or of iron or other suitable material. The sulphurous acid gas issupplied to the receivers through a supplymain M which connects theapparatus with the furnace in which the sulphur is burned and from whichthe sulphurous acid is obtained. The supply-main M is connected with thebottom of each receiver by a pipe b, which is provided with twovalves 1) b one near the supply-main M and the other near the bottom ofthe receiver. The vapors pass into the bottom-part of the receiver,which is provided with a perforated false bottom B, a charging man-holeand man-hole cover E at the top, and a discharging man-hole and manholecover F at the bottom. The vapors pass from the upperpart of onereceiver by a downwardly-extending pipe at to the supply-pipe b of thenext adjacent receiver, said connecting-pipe being likewise providedwith a stopcook 01' at its lower end near its connection with the pipeI). The last receiver of the series is connected by the pipe cl with thepipe I) of the first receiver so that a closed cycle for the gas isobtained. The sulphurous acid gas passes through the bones charged intothe receiver and is conducted through the connecting-pipe d to the lowerpart of the second receiver, then in upward direction through the bonesin the same then to the and third receivers are closed, so thatthe'vapors are compelled to take the course before mentioned. When thebones in the receiver A are saturated with sulphurous acid, the

lower valve b of the first receiver and the valve 01' of the secondreceiver are closed, and the lower valve 1) of the second receiver'opened and connected with the supply-main M, so that the vapors passthrough the second, third, fourth and fifth receivers, which latter isconnected with the fourth receiver by opening the valve d of itsconnecting-pipe d. The saturated bones in the first receiver arepermitted to stand in the same for two or three days, so that theperfect conversion of the bones takes place by the action of the acid.When removing the charge from the first receiver, the stop-cock of thepipe e is opened, so that the receiver is connected with thedischarge-pipe, after which the lower man-hole is opened and the bonesremoved.

The charge of bones in each receiver is supported on the perforatedfalse bottom, which is arranged below the lower man-hole F.

In place of the apparatus described, my improved process fortreatingbones by means of sulphurous acid vapors can also be carried 011in any other apparatus, as, for instance, an apparatus in the nature ofa tall cylindrical shaft which is charged at the top and discharged atintervals at the bottom. During the time when the bones are at rest inthe receivers, the surplus quantity of sulphurous acid which is retainedby condensation, enters into chemical combination with the innerportions of the bones that are not fully saturated. If the batteryconsists of eight receivers, four are always in use for the absorptionof the sulphurous acid, while three are in a stateof rest after theabsorption is completedfand one is in course of being charged ordischarged. After the receiver A is shut 01f, the fifth receiver A beingcharged with fresh bones, is-connected with the receivers, A A A whilereceivers A A and A are in a state of rest. Receiver A which has beenstanding longest, is then emptied, charged with fresh bones andconnected in place of receiver A which is shut OE, With the receivers AA and A and so on in continuous succession. If the size of the severalreceivers be such that each represents one days output, the entire cyclewould be made in eight days, four of these serving for the absorption,three for rest for the purpose of the chemical combination of thesuperficially-condensed sulaccording to rule.

cial clarifying vats.

phurous acid and one day for discharging and charging. Thisbattery-apparatus is especially adapted for places where .no puresulphurous acid gases but mixtures of the same with indifferent gasesare used, such as are obtained from the combustion of sulphur, thefurnace-gases from pyrites, &c. If compressed liquid sulphurous acid beavailable, the operation may be carried on under pressure in separateiron receivers, in which case for every hundred parts by weight of bonesfrom ten to twelve parts by weight of liquid sulphurous acid is passedinto the receiver and the charge allowed to stand until the absorptionof the sulphurous acid has taken place, The small quantity of carbonicacid which is evolved from the bones, is discharged from time to time bya blow-off valve when the pressure becomes too high. Upon completion ofthe conversion, the bones are subjected to the action of a vacuumso asto remove the free sulphurous acid still preshundred pounds of bones twoand a half cubic yards of pure sulphurous acid gas would be required,thequantity being capable of exact measurement by the number of strokes ofthe compressor. After removal from the receiver the bones are soaked inwater for two or three days to remove the soluble salts and especiallythe smelling and coloring matters made soluble by the sulphurous acid.

The boiling down of the bones to glue is now proceeded with. As ironvessels cannot well be employed owing to the acid properties of theglue-solution, wooden vats or vessels lined with lead are used. They arechargedwith the converted bones and with sufficient Water to cover thesame. The heat: ing up to 100 Celsius is effected by means ofsteam-coils or by the direct introduction of steam at the bottom of thevessel. After two or three hours of boiling, the larger quantity of theglue substance is. dissolved and it is best to withdraw the firstsolution in order that the glue may not be decomposed by boiling toolong. vFresh water is then added to the bones to extract the remainingglue-substance and boiled to form a diluted glue-solution, which may beadded to the other in spe- By a third boiling, a very diluted solutionis obtained which is utilized by adding it to the next charge ofbone-material.

When bones that have not had their fat extracted, are used for theoperation, the separation of the fat from the glue-solution must beefiected in the clarifying vats, where it rises to the surface. In thecase of bones from which the fat has been previously extracted, thisseparation of the fat is not necpress.

essary. tralized with milk of lime to remove the phosphates and sulfitesheld in solution. The milk of lime used for this purpose is preparedfrom ten parts of causticlime and one hun- -whereupon the separatedmatters are completely precipitated. The clear bright yellowglue-solution is then drawn off or separated from the precipitate by theaid of a filter- The further Working of the glue-solution into cakes isaccomplished in a known way by evaporating it in open or in vacuumpans,pouring into molds, cooling, cutting and drying. By treating freshbright bones according to this process, a nearly colorless and odorlessgelatineis obtained. The yield of glue is good, amounting to fromsixteen to twenty-four per cent, according to the quality of thebone-material used. The sulfite and phosphate residuum of the bonesremaining after the boiling process, is dried and ground to powder undera light pressure. The inner unconverted and still hard portions of thetubular bones retain their form and are separated from the powderbysifting. Probably owing to adeficiency of moisture, the innermostportions of the hard bones absorb only from three to four per cent. ofsulphurous acid, and they may be again subjected to the action of thesame, but as they form only about ten per cent. of the bones used, anddo not contain much glue-substance, their further treatment withsulphurous acid may be omitted, more especially as the nitrogen of thesame has a certain value as manure.

The ground residuum is not suitable for direct application as manureowing to the sulfite contained in the same. The powder is thereforetreated with sulphuric acid in closed cylinders provided with agitatorsin order that during the formation of superphosphate the sulphurous acidcan be drawn off The hot glue-solution is next new,

in gas form. This sulphurous acid is again utilized by being introducedinto the battery of receivers for the treatment of further quantities ofbones.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. The process herein-described of treating 6o bonesfor producing glue and gelatine from the same, which consists in thefollowing steps: first, subjecting the bones to dry disintegration bythe action of sulphurous acid gas, second, dissolving the brittledisintegrated bones by boiling water or steam, third, neutralizing theacid glue-solution obtained thereby, and lastly, separating theglue-solution from the precipitates for further treatment, substantiallyas set forth.

2. The process herein described of producing glue and gelatine frombones, which con sists of the following steps, first: subjecting thebones to dry disintegration by the action of sulphurous acid gas,second, subjecting the disintegrated or converted bones to the action ofboiling water or steam until an acid glue-solution, containing acidcalcium-sulfite and bi-calcium phosphate, and a residue containingneutral calcium-sulfite, mono-calcium 8o phosphate and insoluble organicsubstances is obtained, third, neutralizing the acid gluesolution, andlastly, separating the clear gluesolution from the precipitate forfurther treatment, substantially as set forth.

3. In the process of treating bones for producing glue and gelatine fromthe same, the dry disintegration or conversion of the bones bysubjecting them to the action of sulphurous acid gas, substantially asset forth.

4:. In the process of treating bones for producing glue and gelatinefrom the same, subjecting the bones to dry disintegration by the actionof sulphurous acid gas up to the point of saturation, and thenpermitting them to stand for a certain length of time, substantially asset forth.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing Witnesses.

MAX SCI-IROEDER. [L. s.]

Witnesses:

H. F. MERRITT, WILLIAM OT'ro.

